Optical vortexes are light beams that travel in helical patterns around their axis of propagation. The electromagnetic waves comprising the beam may cancel each other out at the axis. Thus, the cross-section of an optical vortex beam may resemble a circle of light with a hole aligned at the axis. The helical rotation of such a light beam exhibits an angular momentum that can be used to induce torque in objects on the order of a micrometer to nanometer in size. Thus, an optical vortex beam may be used, for example, to manipulate any responsive material, including cells and tissues.